Coating, adhesive or sealant formulations may include rheological modifiers to reduce viscosity, disperse pigments and improve solvency and flow. Formulations which do not contain rheological modifiers may exhibit a rapid increase in viscosity for a relatively small increase in solids content. The increased viscosity causes the formulation to set quickly resulting in striations in the formulation. Addition of a rheological modifier enables the formulation to flow into a smooth layer before it sets. Conventional rheological modifiers include polyethylene glycols such as Carbowax and polyethylene oxides such as Polyox.
There is a need for a rheological modifier to reduce viscosity and volatile organic content, disperse pigments, and improve the solvency and flow properties of a coating, adhesive or sealant.
Radiation curable coatings are generally composed mainly of radiation curable multifunctional monomers, oligomers and polymers. Restrictions on solvent content in the atmosphere have increased efforts to provide radiation curable coatings which do not contain any volatile components, but instead include components which form either the whole or a part of the hardened film itself. Reactive diluents are used to lower the volatile content of the coatings by reducing the loss of organic solvents into the atmosphere. Reactive diluents are compounds of low volatility which reduce the viscosity of a coating, adhesive or sealant formulation and become a permanent part of the formulation through chemical reaction. Accordingly, reactive diluents are added to radiation curable coatings not only as a diluent, but to reduce viscosity, copolymerize with the oligomers and polymers to form a part of the coating, and contribute to the final properties of the cured film. Examples of reactive diluents for use in coatings are monofunctional acrylic monomers, multifunctional acrylates and methacrylates of alkoxylated and non-alkoxylated polyols such as trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate and 1,6-hexanediol diacrylate and dimethacrylate, difunctional diluents such as 1,6-hexanediol diacrylate and dimethacrylate, and trifunctional diluents such as trimethylolpropane triacrylate and pentaerythritol triacrylate. These reactive diluents pose problems which limit their use in radiation curable coatings. The diluents are known to produce brittle films with severe shrinkage and poor adhesion to substrates, exhibit slow cure response or poor solvency effects, ineffectively reduce viscosity, or cause serious skin irritancy problems.
There is a need for a reactive diluent which exhibits good cure response, low intrinsic viscosity, low film shrinkage, and excellent solvating or viscosity reducing properties.
Formaldehyde is a raw material frequently used in polymeric systems including phenol-formaldehyde, urea-formaldehyde, and melamine-formaldehyde. Exposure to formaldehyde vapors in the workplace is stringently controlled by the use of formaldehyde scavengers. Formaldehyde scavengers capture formaldehyde and hold it in a form having significantly lower formaldehyde vapor pressure. Products such as textiles and plywood typically contain a formaldehyde scavenger to reduce free formaldehyde levels without changing the physical properties of the products. Known formaldehyde scavengers include nitroparaffins such as nitromethane (NM.TM.), nitroethane (NE.TM.), 1-nitropropane (NiPar S-10.TM.) and 2nitropropane (NiPar S-20.TM.), and amino alcohols such as 2-amino-2-methyl-1propanol (AMP.TM.), 2-amino-2-ethyl-1,3-propanediol (AEPD.RTM.) and tris(hydroxymethyl)aminomethane (TRIS AMINO.RTM.), which are manufactured by ANGUS Chemical Company.
There is a need for a formaldehyde scavenger which efficiently, cost effectively, and safely removes formaldehyde from polymeric systems and from any other preparation where free formaldehyde is a problem, without seriously detracting from the performance or physical properties of the system.
Phenol-based peroxide inhibitors have been suggested as a substitute for 2,6-di-t-butyl-p-cresol for use in polyol formulations because of the limited supply of the conventional p-cresol inhibitor. However, the phenol-based inhibitors cause discoloration of the polyol. N-(2-hydroxyalkyl)oxazolidines are known decolorizing agents for removing color-forming bodies from a mixture of alkyl substituted phenols.
There is a continuing need for a decolorizing agent which removes the color from a phenol, amine or other discolored preparation.
Urethane coatings when cured often contain bubbles and pinholes. These bubbles and pinholes occur because moisture in the coating reacts with isocyanate during the curing process.
There is a need for an additive that reduces formation of bubbles and pinholes in urethane coatings.
When urethane coatings are applied under conditions of high temperature and humidity, a phenomenon called downglossing often occurs. Downglossing is caused by the reaction of humidity (water) with isocyanate, resulting in microbubbles on the surface which reduce gloss.
There is a need for an additive that reduces downglossing in urethane coatings by inhibiting the formation of bubbles on the surface of the urethane coating.